Thanks for all the feedback I got on this space series so far. Out of all comments and questions, one loomed large. “Where would we get enough methane from in space and economically so?”
But before we go there, we need to know what it is that we want to do in space. There are two core philosophies that have each very different requirements. On the one extreme end, there is Elon Musk with SpaceX who believes we should be settling on and ultimately terraform other planets and moons.
Naturally, someone who settles on a planet or moon will search to make use of what can be found on that heavenly body. The Moon – but also Mars to some extent- are not known to be rich in organic volatiles humans need to make a living. Those are mainly nitrogen and oxygen to build an atmosphere. CO2 for plant life – yes, it’s a vital need for a space colony. But also hydrogen for water and fuel production.
Thats it for the bulk volatiles. And they are generally not in huge supply on most bodies of the inner solar system. But once you are on a planet or moon, you will try to synthesize them out of other elements as much as you can.
And on the other end of the spectrum, there is Jeff Bezos who looks forward to full life in space. He has chosen the design of an O´Neil cylinder which is basically like a giant drum of a washing machine floating in space. Like the washing machine’s drum, it spins and hence produces artificial gravity through centrifugal forces.
If you want to live in free space, you will place your stations where you can harvest everything you need in the most cost-effective manner. You will also enjoy perfect sunlight as there is no night cycle so the nasty intermittency issue plaguing solar on Earth goes away. And you will want to be close to our central star for optimal solar energy harvesting.
Another massive advantage is going to be that living conditions on those space stations will be optimized for life originating from Earth. Gravity can be precisely calibrated avoiding nasty side-effects of long space stays. And everything else from pressure, air composition, and daylight cycles can be adjusted. Do that on a planet.
The inner solar system will be our playground. The reasons for that are simple. Sheer distance.
For reasons of practicability, we will have to stay within the inner solar system for a long while. True, humans might eventually venture to the outer planets. But you don’t want to depend on them for the sustainability of your colonies and the space fleet.
That being said, the inner solar system is still incomprehensively big by human standards. Just imagine you fly around planet Earth in a commercial airplane. It would take you about two days of fly time. By those standards, the journey to Mars would take about 3000 days or a little less than 9 years. Rockets are much faster than commercial airplanes of course but distance and ease of access still is a factor.
If Methane turns out to be the backbone fuel for space travel as it’s so very nice and easy to produce and store, then we will need better than questionable sources from the moon or whiffy atmospheres on Mars.
We could – of course – direct our gaze towards the Saturnian moon Titan. Who has not seen the pictures from the descent of the Huygens probe onto the surface of this frigid moon? Water exists as rocks there and methane is mostly liquid. Natural LNG – a moon full of rocket fuel.
There is just a little problem.
It would take a starship close to a decade to just get there. If we are already in awe of the distances in the inner solar system, the outer planets and their distances blow the scale for the inner planets to smithereens. How do you build a civilization in space when fuel is so darn far away?
Turns out that the first planet in this solar system visited by a human-made machine was not Mars. It was Venus.
It’s much closer than Mars, its orbital period gives us many more launch windows than Mars does and we need less energy to get there.
And any human colony will have to stay in very close contact with Earth for a rather long time. They will have to do so for technological development and stuff that can’t yet be effectively produced in space. So, easy access to the colony will be very attractive. But there is more.
Up until the middle of the last century, we Earthlings actually thought that Venus was a very nice place to be. Hence the name. Venus was the Roman goddess of love, beauty, desire, sex, fertility, prosperity, and victory. Pretty positive attributes, don’t you think.
Humans imagined Venus as a paradise, closer to the Sun, and potentially inhabited. Before WW2 an imaginary alien more likely came from Venus rather than Mars. The Martians took over in public imagination when it was discovered that conditions on the surface of the planet were significantly less than ideal for human life.
When the Soviets sent their first Venera probes to the planet, they thought that pressure and temperature would be higher than on Earth. But they were not prepared for what happened. The first couple of landers did not make it to the surface in working order. When Venera 7 performed the first soft landing in 1970, we got a first data-glimpse of what hell must look like.
Hotter than a Pizza oven and a pressure equal to 1000 meters below the surface of an ocean on Earth. And it rains sulfuric acid. It’s so unbelievably bad that the first probe just survived 23 minutes on the surface before it got fried and squeezed to death. To this day, no probe made it longe than slightly over 2 hours on the surface of the planet. It’s the deadliest planetary surface we know.
If you stepped out of a spacecraft on the surface of Venus you would be instantly cooked, crushed and dissolved. Don’t worry, you would not feel a thing. Conditions on Venus are so hostile to any life-form we know that the planetary surface is absolutely sterile with almost absolute certainty.
Not an enticing picture – don’t you think?
But on second looks, Venus might be our best chance to become a real spacefaring civilization. Because whatever strategy anyone would follow for his personal space project will require two things. Lots of stuff to build things and lots of energy to run them. And don’t even think about lifting all that out of Earths deep gravity well. Even with vastly cheaper rockets now, that would still be a forbiddingly expensive undertaking.
And when it comes to stuff and energy, Venus might actually live up to its former reputation as a Garden Eden.
Because we do not need to go down to the scorching surface of the planet to get all the bulk material we need. The atmosphere has it all in vast quantities.
The Venusian air is composed of 96,5% CO2 and about 3% Nitrogen with some trace elements sprinkled in between. The Nitrogen comes in handy for creating breathable air. 3% does not sound like much but remember that the Venusian atmosphere is also about 90 times denser than the Earth’s. This means that by volume, the 3% on Venus corresponds to the 78% we have in Earth’s air. That’s plenty to go around.
That being said, considering how dense the Venusian atmosphere is, even the smaller trace elements in it are very interesting to exploit. Add in great solar power due to its closeness to the sun. Plenty of energy for the extraction and transformation processes.
See how that can be done in next week’s blog post.